The administration of corticosteroids to treat inflamed tissue is an important and widely-used treatment modality, especially in dermatology. Since topical corticosteroids can act to depress local antimicrobial defenses, it would be very helpful to be able to use such compounds together with antimicrobial agents in the topical treatment of skin disorders. See, Raab, Dermatologica, 152 (Suppl. 1), 67-79 (1976) and Raab, Br. J. Derm., 84, 582 (1971). C.sub.5 -C.sub.12 carboxylic acids, especially caprylic (octanoic) acid, are lipophilic materials known in the art to be effective, broad spectrum antimicrobial agents which may be used topically. See, Keeney, Bull. Johns Hopkins Hosp., 78, 333 (1946); U.S. Pat. No. 2,466,663, Russ, et al., issued Apr. 5, 1949; and U.S. patent application Ser. No. 918,532, Stone, filed June 23, 1978.
It is well-known in the pharmaceutical arts that negative interactions can occur when certain types of antimicrobial agents, especially lipophilic antimicrobials, are used together with corticosteroids in combination therapy. Thus, for example, Dobozy, et al., Hautarzt, 1976 (Suppl. 1), 11-13, teach that percutaneous absorption of topical salves containing the lipophilic compounds oxytetracycline, clortetracycline and doxycycline is inhibited by the addition of glucocorticoids, such as prednisolone, hydrocortisone-17-butyrate, betamethasone valerate and dexamethasone pivalate. Raab, et al., Chemotherapy, 15 (1), 26-34 (1970), indicate that the corticosteroids cortisol, methyl prednisolone hemisuccinate and fluocinolone acetonide significantly reduce the antibacterial activity of dodecyldi(beta-hydroxyethyl)benzylammonium chloride and dodecyl triphenylphosphonium bromide (both of which are lipophilic compounds). Raab, Acta. Derm.-Venereol., Suppl. 52 (67), 32-39 (1972), teaches that fluocinolone acetonide acetate causes a decrease in the fungicidal activity of 1-p-chlorobenzyl-2-methylbenzimidazole and the bactericidal activity of dodecyldi(betahydroxyethyl)benzylammonium chloride; yet, there is no impairment of microbiological activity noted when non-lipophilic antimicrobials, such as nystatin, natamycin, or neomycin, are combined with fluocinolone acetonide. Finally, Zygmunt, et al., Appl. Microbiol., 14(6), 865 (1966) disclose a wide range of steroid interference with the antifungal activity of a group of lipophilic polyene antibiotics.
Thus, based on the art, one would have expected negative interactions when corticosteroids were used together with lipophilic C.sub.5 -C.sub.12 fatty acid antimicrobial agents in combination therapy. Yet, surprisingly, it has now been found that such combinations can be made, exhibiting outstanding anti-inflammatory and antimicrobial efficacy, without any negative interactions.
Accordingly, it is an object of the present invention to provide effective topical antimicrobial and anti-inflammatory compositions containing C.sub.5 -C.sub.12 fatty acids and corticosteroid components.
It is a further object of the present invention to provide a method for the effective topical treatment of inflammatory skin disorders.